ESE's works engine tuner

[F5 Dave]

I just read the Freetech 50 rules online. What a joy of simplicity and clarity! Well done Frits. Then I look at the MNZ rules and cringe.

If we were to introduce those same rules here, I suspect it would force everyone who wanted to compete to move to nicasil-bore cylinders, since oversize cylinders are not allowed. Older cast iron cylinders and those with steel liners would be eliminated since most of them are already at least one oversize. Given the investment some of us have in this old stuff (pretty much mandated by our own bucket rules), a Freetech 50 class might be less attractive initially.
Obviously, these old engines would no longer be competitive in the face of MX 50 engines and Euro race engines, so would fall away anyway, but it would be nice to have an upgrade window. Possibly we could change the rules slightly to allow minimal overbore. Or we could run two classes of 50, Freetech and Vintage, but this is probably not feasible given the small number of people who race F5 now.

It's a fantastic class though, no argument.

Its really a cruel twist of history that 50 and 100cc bikes were popular in the 70s and 80s. But for whatever reason we didn't get the kids all on Derbis and AM6 engined bikes and they all bought RGV250s instead due to our lax licencing laws of the time and perhaps disposable income. Or maybe jap import cars and the promise of carnal wagon action. Fools!

[jonny quest]

Found something interesting while checking out the Athena GET aftermarket ECU for the KTM TPI system...
http://www.getdata.it/data/documenta...IP_0039_AA.pdf

Attachment 336256

The 'injectors support kit' moves the injectors to a spacer plate between the reed block and crankcase, and plugs the existing transfer port bungs.
I also downloaded the map pack and included was a map for 'indirect injection'. Couldn't find any other info on it anywhere. Must be some performance improvement, is a lot of effort to go to to make something worse.

Update on my bike, I had the cylinder 'bored' by the other shop in Australia that does Nikasil. Got it back to adjust the ports before plating, the bore is offset 0.35mm toward the front at the top and 0.30mm toward the back at the bottom. Turns out he used a hone for the whole 2.1mm!! The guy says it 'should be ok', I'm really not impressed, not sure what to do with it from here. The difference in squish front to back would be 0.3mm so that limits what I can do there, if it was bored out to 72mm it would clean up, but I don't want to go there.

How can you hone aluminum that much? YZ250 cyl, right? I'd make them biy me a new cylinder. That could cause crank and piston failures. Especially if it's not square side to side.

Interesting on GET. Are you going to buy that system and retrofit to YZ?

[Michael Moore]

I may have missed seeing it discussed, but would there be a benefit to having two separate cooling circuits on a 2T? That would be a high temp circuit that does the exhaust port/manifold/head and a low temp that does the crankcase/transfers. I'd think the case/transfers would tend to run cooler anyway, so why use the hotter water that has gone to the hot spots of the top end on them?

Electric pumps are easy to get and there'd be no need for a temperature control on the case circuit, just circulate the water non-stop through the heat exchanger. A controlled pump (like the Davies Craig) could circulate coolant on the hot circuit and control the temperature to whatever is desired.

I suppose there'd need to be enough power increase from lower case temperatures to offset the weight of an extra pump/heat exchanger.

Does that make any sense?

[koenich]

Pure enthusiasm Dave!

Massive effort, love it! And by the end of the season you hopefully have a Star Alliance Gold card

I'm thinking about doing the Hockenheim round, as it is just around the corner from my hometown. Need some fairings though

[mattology]

that athena get seems like a major step backwards

[husaberg]

I may have missed seeing it discussed, but would there be a benefit to having two separate cooling circuits on a 2T? That would be a high temp circuit that does the exhaust port/manifold/head and a low temp that does the crankcase/transfers. I'd think the case/transfers would tend to run cooler anyway, so why use the hotter water that has gone to the hot spots of the top end on them?

Electric pumps are easy to get and there'd be no need for a temperature control on the case circuit, just circulate the water non-stop through the heat exchanger. A controlled pump (like the Davies Craig) could circulate coolant on the hot circuit and control the temperature to whatever is desired.

I suppose there'd need to be enough power increase from lower case temperatures to offset the weight of an extra pump/heat exchanger.

Does that make any sense?

I think I do Michael, use the radiator on the Crankcase side only with a heat exchanger for the top end. you would need to use a large surface area to get the appropriate area for cooling though but a small marine oil cooler would likely work.

[Michael Moore]

I think I do Michael, use the radiator on the Crankcase side only with a heat exchanger for the top end. you would need to use a large surface area to get the appropriate area for cooling though but a small marine oil cooler would likely work.

We may have a small terminology misunderstanding since I was using "heat exchanger" to refer to a "radiator" (per Carroll Smith's "Prepare to Win" definition that they are water/air heat exchangers) but I hadn't considered using a liquid/liquid heat exchanger since I've never had occasion to use one in the past. I was envisioning a "radiator" for each circuit.

So would I be correct that you do think there would be some advantage to having two (a high temp and a low temp) separate cooling circuits so the low temp circuit can more easily stay "low" by not having to deal with the high temp coolant?

cheers,
Michael

[wobbly]

So here are the first results of going over Robs GP - NSR110 engine with the intent of fixing any glaring issues,then doing a trick pipe design.
By small alterations to the pipe temp file, and realizing that a RV engine at WOT,way off the pipe will carburate like shit due to intake wave interaction,then
the sim Vs the dyno is a pretty good match.
Then the first two things to look at are the Mach numbers in the Ex duct exit, and the stinger nozzle.
To do this you must first run the sim with the Ex transducer at the header start length ( and name that file ),then rerun it ( and rename the file ) with the transducer length
within the nozzle.
From these results you can see that both are miles off the 0.8 Mach rule of thumb.
Then we look at TuBMax,and this shows that the combination of bmep,ignition lead and stinger size is way down overall, but more so in the midrange where it never gets even
close to the 1000* deto limiting guideline.
More to come as I work thru any further shortcomings.

[TZ350]

.
Very interesting, great info, loving learning more about how to use EngMod professionaly, thanks Wob.

[wobbly]

So sticking with the original pipe initially,here is the result of welding or inserting the Ex duct and reducing it to 34mm outlet size.
Along with this making a new spigot to match the smaller cylinder exit to the stock pipe header.
Check the rise in the resultant exit Mach.
We are already seeing that the powervalve ramp is now becoming mismatched,with a big dip in the midrange.
Also the taper in the spigot is already getting very steep, as the RS125 pipe header size ( 41mm ) is way too big for an engine only making 30 Hp as the effective area
of the port ( even set a 200* duration ) is only 35.8mm diameter.

[Nath88]

How can you hone aluminum that much? YZ250 cyl, right? I'd make them biy me a new cylinder. That could cause crank and piston failures. Especially if it's not square side to side.

Interesting on GET. Are you going to buy that system and retrofit to YZ?

Yeah YZ250 cylinder, its definitely a lot of material to remove. Doesn't appear to be squif side to side, but it's a lot more difficult to measure.
I'll give them a call today and lay it down, then back it with a letter of demand. I can get another for $250 or so, but I'll give them the option to source me a used unmodified cylinder.

I was thinking about a retrofit... It wouldn't be too difficult. Not sure that I trust the oil delivery system on them though and premix is not an option.

[TZ350]

So sticking with the original pipe initially,here is the result of welding or inserting the Ex duct and reducing it to 34mm outlet size.
Along with this making a new spigot to match the smaller cylinder exit to the stock pipe header. Check the rise in the resultant exit Mach.
We are already seeing that the powervalve ramp is now becoming mismatched,with a big dip in the midrange.

Being walked through it, it makes so much more sense.

[wobbly]

So as a last sticky plaster fix for the existing pipe,we drop the cylinder exit size to 33mm,add 10mm to the spigot length ( you need a new one anyway ) as this reduces the abrupt taper
out to the header, and reduce the stinger from 23 to 22mm.
Then I adjusted the PV curve a bit to pull up the mid range dip.
All this fiddling with the existing components really only points to where to start with a full house effort.
The Mach is getting there,the PV is looking more effective,and it loves the smaller nozzle.
The TubMax is still way off,but as yet I havnt touched the ignition - will leave that till we start making serious power with real pipe/port synergy.

[tdc211]

Early today. I ran the rs125 pipe in the sim on my proven 34.5hp 104cc case reed. Just to see what that big header 125 pipe looked like on mine . Not saying robs engine is anything like mine.

But mine can make the power. With reliability. With a higher case comp than ideal and a small reed block. I use a 300 pipe temp in real life.
(I have not tried to make a pipe. To run at 400c yet)
This was all figured out ,by testing and watching the delivery ratios and everyrhing else in sim and measuring pipe temp in the belly on the dyno. And knowing when to much delivery short circuited and killed power dead. Even with as good as tranfer angles as you can put in that cylinder. After a while you get a feel for it. I am not a expert. I just kept at it. Make it work and knowing why was my goal I also had help along the way. Like many of us.

Long time ago wob said no 100cc engine has gone 34 or 35hp. Mine's 104cc . 32mm carb. Free blows for life? Lol.
Took forever to achieve. The single best thing I did. Was make a pipe. It was worth more than all the tranfer angle work.
But the pipe probably would never work without the tranfers radius/angles. Now i finially bumped up the midrange to 23 at 9000. And good peak. Matches sim really well.
I just saying. Wish more sim pipes where tested on this great thread. And by no means am I saying pipe below can not be made better . But here is rs125 at 300 and 400c vs my pipe at 300c in sim. On a 104cc engine. Plus I know my works in real life
You will notice.. 36mm header. Same as my ex effective area.
32mm outlet at flange that transitions to a 36.

[jonny quest]

TZ350, what Wobbly said about RV and pipe off throttle. Maybe a RV is next to impossible to EFI